<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
  <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
  <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
  <title>Document</title>
</head>

<body>
  <div id='render'></div>
  <script type="text/babel">
    function Home(props) {
      return (
        <h1>现在是{props.date.toLocaleTimeString()}</h1>
      )
    }
    class Clock extends React.Component {
      constructor(props) {
        super(props)
        this.state = { date: new Date() }
      }
      componentDidMount() {
        this.timerID = setInterval(() => this.tick(), 1000)
      }
      componentWillUnmount() {
        clearInterval(this.timerID)
      }
      tick() {
        this.setState({
          date: new Date()
        })
      }
      render() {

        return (
          <div>
            <h1>hello, World</h1>
            <Home date={this.state.date}></Home>
            <Home date={this.state.date}></Home>
            <Home date={this.state.date}></Home>
            <Home date={this.state.date}></Home>

          </div>
        )
      }

    }
    ReactDOM.render(
      <Clock />,
      document.getElementById("render")
    )

  </script>

</body>

</html>